System of television



July 12, 1932.

J. H. HAMMOND, JR SYSTEM OF TELEUSION Filed Dec. 6. 1928 6 Sheets-Sheet l WMNN INVENTOR HAYS HAMMOND JR.

July l2, 1932. J. H. HAMVMONQD,' JR 1,867,542

SYS TEM OF TELEVI S ION Filed Dec. 6, 1928 I s Sheets -Sheet s INVENTOR AYS AMMOND JR.

J H M MM A ORNEY July 12, 1932. J. H. I-I-IAMMOND, JR

SYSTEM OF TELEVISION Filed Dec. 6, 1928 6 Sheets-Sheet 4 BY; I

OH HAYS HAMMOND JR- A ORNEY July 1-2, 1932. J. H. HAMMOND, JR 1,867,542

- SYSTEM OF 'TELEVISION v Filed Dec. 6, 1928 6 Sheets-Sheet 5 k 4 w Raven 120 l 12? a0 IMOUR INVENTQR JO HAYS HAMMOND .nz.

July 12, 1932. J. H. HAMMOND, JR

SYSTEM OF TELEVISION Filed Dec. a, 1928 s Sheets-Sheet 6 JR. Q

INVENTOR JOHN HAYS MMOND BY 1 4a A ORNEY Patented July 12, 1932 UNITED STATES PATENT OFFICE sxs'rnu or rnnnvzs'ron The object of this invention is to provide means whereby events may be recorded as theytranspire in a simple and eflicient manner and later distributed tant oints.

vide means whereby records of transpiring events may be taken and transmitted by radio or land wire at a later period and under bet ter conditions than would otherwise be pos parent upon reading the accompanying specification taken in connection with the drawm ith the present system of television it is necessary to analyze the scene occurring before the transmitter and immediately transmit it over radio or land wire receiving the impulses thus transmitted and immediately reproducing the image at the receiving end. It is obvious that if an event shduld take place say early in the morning in Europe it would beimpracticable for people in North. America to view the event at this time, as theevent transpiring by Greenwich standard time would transpire 5 hours earlier than eastern standard time.

With this end in view, the present invention is directed to the design and construction of the necessary apparatus for enabling an event transpiring in London say at 9 oclock to be recorded and transmitted over the cable or radio system when thebest condition should,

exist and recorded or stored in North America and exhibited in the various theatres when! ever desired as at the matinee theatre time or even later in the evening.

With this method also it is possible to exhibit the picture a number of times, that is,

as desired at dis- A urther object of this invention is to pro- Application filed December 6, 1928. Serial 1T0. 824,078.

an event which has transpired in England in the morning should be recorded and transmitted during the best hours of radio transmission during the day, received in New York andrecorded on the instrumentalities' rovided byv the inventor and then later exhi ited at the shows a plurality of times during the course of the evening.

attention is invited to the accompanying drawingsin which: Fig. 1 is a plan showing the utilization of the present system;

Fig. 2 is an analyzer;

Fig.3 is a plan view of same;

Figs, 4,. 5, 6 and 7 are figures showing in apparatus for carrying out the invention; viz. Fig. 4 shows the scanning or analyzing means together with the amplifier and magnetic recorder, Fig. 5-shows the magnetic reproducer connected with a transmitter for transmitting the recorded television, Fig. 6 shows a receiver for receiving. and magetically recording the transmitted television and Fig. 7 shows a magnetic recorder for exhibit ing or projecting the recorded television;

Fig. 8 shows the amplifier for amplifyin the impulses from a photo-electric cell an feedingthem to the magnetic recorder; Fig. 9 shows the transmitter system for receiving impulses fromducer and transmitting them;

Fig. 10 shows the lay-out for connecting a" I multiple number of recorders or projectors; Fig. 11 shows .the'receiving apparatus for receiving amplifying and supplying amplified television impulses to the recorder, and, Fig. 12 is a general view of the magnetic recorder ofthe invention. Having-thus briefly described the figures illustrating the invention, attention is now particularly invited to Fig. 1 which is a ma repesenting the North Atlantic Ocean wi England at the right and North America at the left hand thereof.

There is shown, just taking place, some event, such as, a street parade at A, say in London, .England, at 11 a. m., Greenwich standard An analyzer and magnetic Having thus briefly described the invention "diagrammatic form the lay-out of the various the magnetic repro- 7 recorder have been transported to the scene of the event on a truck and the event is recorded on the magnetic recorder. The truck then drives to the laboratory B, from the 5 scene of the event, and the recorded picture is transmitted by land wire to C, from whence it is transmitted by radio and received at D and transmitted by land wire to the points E, F, G, and H. The time of transmission from B to C may be at say 11:30 whereas the transmission from O by radio to D may take place either at the same or a later time, say at noon Greenwich standard time. The transmission then would be received at D at 7 a. m. eastern standard time and might be either immediately transmitted to the various stations E, F, G, and, H or retained at D and transmitted at some later time, say 8 a. m. eastern standard time. Transmission to the points E, F, G, and, H of course, may take place at different times as may also the transmission to the remote points K, L, and, M either by land wire or by radio, the latter transmission being indicated as taking place from the transmitting station E to which the received impulses from England are transmitted by land wire.

The picture impulses received at the points L, K, and M would berecorded and transmitted to the motion picture houses 0, N, R, and, P whenever desired and recorded there and then projected at the afternoon matinee and later in the evening as desired; Attention is now particularly invited to Figures 2 and 3 which as has previously beenstated, show the elevation and plan views respectively of the analyzer. The same genera mechanism may be utilized as the projector by a proper substitution of component parts. The. analyzer comprises an enclosure 11 suitably mounted on a tripod 12. The casing or enclosure is provided with an aperture 13 through which the image of the picture is received and reflected by means of the revolving mirror wheel 14 to the revolving mirror wheel 15. Forrotating the two mirrors the motor 16 is provided which is adapted to directly rotate the mirror wheel 14 and through the worm gears 17 and l8the mirror wheel 16 at a reduced speed. The image is reflected by the two mirrors 14 and 15 focused by means of the lense 19, adj usted by the focusing screw 20, to the photo-electric cell 21 through the aperture 22. 55 Figure 3 shows a plan view of the analyzer taken on the line 3-3 of Fig. 2, having however, a slight modification which will now be described. v i

In Fig. 3, the analyzer has the driving motor 23 directly connected to the shaft 25, by means of which the motor 23 drives the rotary mirrors 14 and 15 through the gearing 24 and 18 respectively.

P Fig. 4 shows the analyzer 30 equipped with 1 the photo-electric cell 21 for analyzing the magnetic recorder 53.

picture to be transmitted. The photo-electric cell supplies current impulses to the amplifier 31 by means of which the impulses are amplified'and recorded on the magnetic recorder. 32. The analyzer 30 and the magnetic recorder 32 are driven in synchronism by means of a common connection to a-given source of alternating current which is supplied through the switch 33.

Fig.- 5 shows the magnetic reproducer 4O which is adapted to supply. the current picture impulses to the amplifier 41 by means of which they are amplified and supplied to-the transmitter 42 to be transmitted through the i antenna, 43. The ma netic reproducer is 30 driven at a fixed speed by means of constant frequency alternating current supplied through the switch 44.

Fig. 6 shows the receiver 51 forreceiving the electromagnetic impulses representing the picture to be displayed and includes the antenna 50 for supplying these impulses through the receiver 51, which in turn, supplies them through the amplifier 52 to'the The recorder 53 is 00 supplied with the required constant fre uency alternating' current through the switc 54.

Fig. 7 showsthe magnetic reproducer 60 which is adapted to supply the projector 63 through the amplifier 61. The amplifier 61 supplies the varyingirhpulses to the light source 62 the light of which isadapted to be distributed or projected over the screen 64 by means of a projector 63. The projector 63 and the reproducer driven in synchronism by the constant fre-- quency alternating current supplied by the switch 65. f

Fi 8 shows an impedance coupled amplifier or receiving the impulses generated by 1 a photoelectric cell and supplying them to a magnetic recorder much amplified. The impulses are impressed by means of. the lead 70 upon the grid 71 and the filament 76 of the thermionic device 72. The filament 76 of the 1 device 72 is adapted to be supplied by the lowpotential battery 77 in the usual and well-known manner. The tubes 73, 74 and 75 are adapted to have their filament su plied by the same low potential source 77. Xcross .115 the input leads 70 of the amplifier are r0- vided the impedance 81 and the biasing attery 82 inseries. The output of the tube 7 2 includes the p ate, the impedance 83 and the high potential source 78. For impressing the amplified potential of the plate. circuit of tube 72 upon the grid of the succeeding tube Y 7 3 there is provided the coupling condenser 84 and shunted across 73 is the impedance 85. For providing a grid bias for the input, the biasing battery 7 Sl-is provided in the usual and well-known man ner.

Similarly the output of the tube 73 in- PM eludes the impedance 86 and the high poten- 60 are adapted to be the input of the tube put of the tial source 78 andfor impressing the amplified potential variations of the device 73 upon the input of the tube 74 thereis provided through the impedance 88 by means of the common biasing battery 79. The outtube 74' is completed in the same manner and the input of the device 75 is also similarly arranged with the exception that additional grid biasin batteries 80 may be provided in series wit the input 89 as desired. The output of the device 75 is adapted to be either directly impressed upon the magnetic recorder as will be described hereinafter, or'control a transmitter for broadcasting the picture impulses. Fig. 9 shows the transmitter for transmitting high frequency oscillations modulated in accordance with the picture impulses as supplied through the amplifier shown in Fig. 8. The transmitter comprises the oscillatory circuit including the oscillator tube 91, input amplifier circuit 92 adapted tobe supplied with the picture impulses through the connection 90, a signal frequency choke 93,. and high potential source 94. The output of the oscillator, 91, is supplied to the antenna system, 95, in this case shown as a couple, in the usual manner.

As has been previously pointed out, Fig. 10 shows the connections for connecting a plurality of recorders or projectors. The connection 120 represents the output of a re ceiver amplifier and said output may be connected to a plurality of distributors terminals 121, 122, 123, etc. These terminals may be connected to eithera recorder or a projector or to a transmission line for transmitting the picture impulses either by wire or by radio. i

Fig. 11 shows'a receiver for cooperation with the transmitter of Fig.- 9. The antenna 130 is connected in the usual and well-known manner to the closed oscillatory circuit composed of the capacity 133 and the inductance 135 which circuit is inductively related to the tuned circuit composed of inductance 136 and the capacity 137 whichlatter circuit is adapted to impress on the grid of the thermionic detector 138 the high frequency energy received. The grid return of said detector is completed through the grid biasing battery 161 the purpose of which is t'oso bias the grid ofthe detector tube that it will perform the ordinary detector function. The plate circuit of the detector 138 includes the feedback inductance 139 and the circuit composed of the bypass condenser 143 and the source 140. The rectified current impulses are impressed through the coupling: condens er 145 upon the input of theamplifier device 147. The rectified current impulses are impressed through the coupling condenser 145 upon theinput of the amplifier device147.

, 154 to the biasing outputof the amplifier device 155 is com The output cirt.

The impedance 146 is connected across the input of the said device 147 to the proper biasing source 142in the usual and well-known manner. The output of the amplifier device 147 is connected to the impedance 148through the high potential source composed of the high potential batteries 1'49 and 141. For impressing the audiofrequency potentials upon the amplifier device, 151., the condenser 149 is provided and for impressing the prop er bias upon the grid of the amplifier device 141 the grid return is connected through the impedance 150 and the biasing source 142 in the usual'and well-known manner. The output of the amplifier device 151 is completed through the impedance 152 and the high potential sources 141 and 140- For impressing the audiofrequency' potential on the grid of the amplifier device rovided. For impressing theproper grid bias upon the grid of the amplifier device 155 the grid is connected through the impedance sources160 and 142. The

pleted through the output impedance 156 and the high potential sources 140 and 141. For impressing the output of the device 155 upon the output circuit, there is provided the output condenser'1'57 and across the output the impedance 158 is shunted in the usual and well-known manner.

Referrlng'now more particularly to Fig.

155 the condenser 153 is 12, there is shown the magnetic recorder which forms an important feature of the sys-. tem of the invention. The recorder comprises the frame 170 which is adapted tosupport the two rotatable reels 171 and 172. The reels 171 and 172 are for t e pur ose of storing-the magnetic recording ape 1 the reels is caused by means of the gear 174 fixed to the shaft of the reel 17 2, and adapted to be driven by the worm gear 176 which is operatively disposed thereto and actuated by the motor 177. For guidingthe tape during its passage between'the reels 171 and 17 2 there are provded the two rollers 178 and the smooth cooperating rollers 179. Disposed between the groups of rollers and supported by the supports 183 is the electromagnet 181, the'wedge shaped pole pieces 182 of which are closely associated with the moving tape 173.- The winding of the electromagnet is ada ted to be supplied with a varying current by t e leads 184.

' The operation of the system is as follows In theoperation of the analyzer shown in Figs. 2 and 3 when it is desired to record an event, the motor is started by closing the controlling switch (not shown). This causes the primary and secondary mirrors 14 and 15 3 and rotation of l ties proportional to the succession of light'impulses transmitted from various points of the succession. The mirror 14 is run at sue a speed that two-hundred twenty-five faces are brought opposite the opening 13 while the mirror is moving from one face to the next face in front of the lens 19. In this way the mirror 14 will pick up light transversely from the scene two-hundred twenty-five times while the mirror 15 is reflecting the light from the top to the bottom of the mirror 14. Thus the scene is divided up into two-hundred twenty-five horizontal lines which are successively run across the lens 19. The light from each point of the scene is therefore brought successively to the opening 22 and thence to the photocell 21.

The current from thiscell is then amplified by any suitable amplifying system, and the output of the amplifying system connected to the magnetic recorder shown in Fig. 12 through the conductors 184. These conductors are connected to the windings of the electromagnet 181 which is made of para-mage netic material. The pole pieces of the electromagnet are wedge shaped and are located in close proximity to'the magnetic tape 173 as previously stated. This magnetic tape 173 which may he of any easily magnetized material is rapidly fed from the reel or spool 171 to'the reel or spool 172 by means of the motor 177 which is started in operation the same time as the motor 16 of Fig. 2 or the motor 23 of Fig. 3.

The current flowing through the winding of the magnet 181 causes rapid fluctuation in the intensity of the magnetic flux between the pole pieces of the magnet which causes a proportional magnetization in the tape 173. It will thus be seen that the magnetization of the tape will be proportional to the intensity of the light received by the photo-electric cell 21 so that there Wlll be recorded on the tape asuccession of magnetization intensiscene being taken. The speed of the analyzing is such that it covers the field in th of a second or less as may be required and a fixed ratio is established between the speed of analyzing and the speed of the tape.

When it is desired to transmit the scene which has been recorded to some distant place, the magnetic tape is placed in a magnetic reproducer which is essentially the same as the magnetic recorder shown in Fig. 12. In this machine the magnet 181 is a permanent magnet or is provided with a small magnetizing coil. As the tape is passed through the machine there is avariation in the magnetic path of the magnet and thus small current .is induced in the windings of the magnet. These currents are amplified by the amplifier as shown in Fig. 8 andthe output of this amplifier is utilized to' control the transmitter, the energy of which is radiated into space by a suitable antennae as shown in Fig. 9. The fluctuations of this energy will there- ,fore be proportional to the fluctuations in the current produced in the windings of the magnet 181, these .in turn being proportional with the magnetization of the magnetic tape 173. This energy is received by a receiving and amplifying system which may be similar to that shown in Fig. 11. The output of the amplifiers -is connected to the windings of the magnet of the magnetic recorder similar to that already described and illustrated in Fig. 12. In this way the fluctuations of received energy will be transferred to the variations in the'magnetization of the second magnetic tape.

lVhe-n it is desired, this magnetic tape may be put in a magnetic reproducer which is connected to an amplifier, the output of which controls a jariable light source in a wellknown manner. 'The light from this source is then reflected through a lens system and rotating mirrors in a reproducenall of which are similar to those of the analyzers shown in Figs. 2 and 3 with the exception that a light source is substituted for the photo-electric cell 21. The intensity of this light source is controlled by the amplified magnetic impressions recorded upon the tape 173 of the reproducing apparatus. The light from the projector is allowed to All upon a screen upon which it appears as a reproduction'of the scene originally scanned by the analyzer. V

Referring now again to Fig. 1 this figure shows in a diagrammatic way the complete operation of this system. Say for example that there is a parade taking place in London at 11 a. m; Greenwichtime. The analyzer would be placed at A and connected to a recorder in a truck both of which could be adjacent to the line of march. After the parade is over the tape from the recorder would be taken to convenient laboratory as at B from which say at 11.30 it could be transmitted by land wire to a transmitter. This transmitter could for instance he the transmitting station of, Clifton, England. At a convenient time, say at 12 noon Greenwich time, the tape at 0 would be placed in the transmitter and wireless impulses sent out which would he received at any number of receiving stations. The station D located in New York. would receive it at 7 a. m. eastern standard time. From D it would be transmitted when convenient, say at 8 a. m. eastern standard time overland wires to the theatres designated F, G, and H and to the transmitting station at E, also over long distance wires to a receiver located in the station K at some distant place, such as Boston.

From the transmitting station at E, it

could be sent, say at 9 a. In. eastern standard time by radio to receiving stations as L and M located for example at Buffalo and Washington.

From L the impulses could be transmitted to a theatre in Bufialo, designated as O and a from M to two theatres located in Washington, designated as P and R. The tapes upon which the impulses were recorded at the various theatres, mentioned, would be stored until it was desired to display the picture, say at 2 p. m., eastern standard time, at which time they would be run through the reproducing apparatus operating the projectors described.

In this way it is seen, that an event which takes place in England in the morning, when it would not be convenient to have it shown in New York, may be stored at suitable places and transmitted at convenient times to any number of theatres where it may be displayed when it is desired.

-It is of course obvious that it vwould be possible to reproduce the magnetic impression recorded upon the tape 173 any number of times it should be desired, as for instance the theatres might repeat the picture which they had recorded upon their own magnetic recorder a number of times.

It is to bedistinctly understood that the invention is not limited to the details of the specification as the means used may be varied.

Having now described my invention, what I claim is:

1. The method of television which comprises analyzing a scene and recording the impulses produced thereby upon an electromagnetic tape, transmitting said tape to a studio, electromagnetically reproducing said impulses from said tape and transmitting the reproduced impulses, receiving and recording said'transmitted impulses, at some later time reproducing said transmitted impulses and retransmitting said reproduced impulses, receiving said retransmitted impulses, recording said last mentioned impulses and at some later period of time reproducin 581d. last mentioned recorded impulses an projecting a beam of light controlled inaccordanoe therewith to re-form the originally.

analyzed scene.

2. The method oftelevision whichcomprises analyzing a scene and recording the mipulses produced thereby, transmitting the record of said impulses to a studio, reproducingsaid impulses, transmitting the reproduced impulses, receiving and recording said transmitted impulses, at some later time reproducin said transmitted impulses and retransmittmg said reproduced impulses, receiving said retransmitted impulses recording said last mentioned impulses and at sdme with to re-form the originally anal zed scene.

later period 0 time reproducing said last mentioned recorded impulses and projecting a beam of light controlled n accordance there- 3. Apparatus for television w ich comprises means foranalyzing a scene, said ana lyzing means consisting of two mirror wheels mounted at right angles and adapted to revolve at such speed that one will scan the scene to be analyzed in one direction while the other will scan the scene to be analyzed a largenumber of times, means for producing electrical impulses varying as the light intensities of the various portions of the scene being analyzed, means for amplifying the impulses produced by said analyzing means, electromagnetic means for recording the amplified impulses, said recording means comprising a magnetic tape, reels for the stora e of said magnetic tape, means for moving said reels at a predetermined speed, means for guiding the tape'between said reels, and electromagnetic means interposed between said guide mea.ns for impressing thereon electromagnetic impulses in accordance with said electrical impulses, means for reproducin said recordedelectro-magnetic impulses, sai 7 last means being similar to said recording means, means similar to said analyzin means for reproducing the scene originally .ana- 9 lyzed, and means interposed between said electro-magnetic reproducing machine and said projecting machine fdramplifying theimpulses generated by, said reproducing means.

4, Apparatus for television which comprises means for analyzing a scene, said analyzing means consisting of two mirror wheels mounted at right angles and adapted to revolve at such speed that one will scan the 7 scene to be analyzed in one direction while the other will scan the scene a large number. of times in the other direction, means for roducing electrical impulses varying as the light intensities of the various portions of the, scene being anal zed, electromagnetic means for recording t e impulses thus produced, saidrecording means comprising a magnetic tape, reels for the storage of said magnetic tape, means for movingsaid reels at a predetermined speed, means for guiding the tape between said reels, and electro-magnetic means interposed between said guide means for impressing thereon electro-magnetic'irnpulses varying in accordance with said electrical impulses, means for' reproducing said recorded electro-magnetic impulses, said-last mentioned means being similar to' the recording means, and means similar to the said analyzlng means for reproducing the scene originally analyzed. 7 q

5. Apparatus for tGIGVISlOII which comprises means for analyzin' a scene, means for roducing electrical impu ses vary ng as the light intensities of the various portions ofthe scene being analyzed, electromagnetic I means for recording the electrical impulses, said recording means comprising. a magnetic tape, reels for the storage of the tape, means for moving said reels at a predetermined speed, means for guiding the tape between said reels, and electro-magnetic means interposed between said guidemeans for impressing thereon electromagnetic impulses varied in accordance with saidelectrical impulses, means for reproducin said recorded e eetromagnetic impulses; an means similar to said analyzing means forrepreducing the scene origmall anal zed.

gOH HAYS HAMMOND, JR. 

